Sun28November0440PM 28

A 75-year-old lady has taken an inadvertent overdose of her digoxin 125 mcg tablets and is now presenting as a GP referral with a sinus bradycardia (rate 45/min), lethargy, vomiting and visual disturbances.

She has a background of chronic renal impairment (baseline creatinine 150 µmol/L), hypertension and congestive cardiac failure. Her blood pressure has been on the low side but she has remained alert and oriented and otherwise well in herself. She is being monitored on the cardiac ward. Her bloods have been taken (potassium is 5.3 mmol/L) and digoxin now stopped.

Over the past two hours you notice that her urine output has dipped and she has started to become symptomatic. A repeat ECG now shows third degree atrioventricular (AV) block with profound bradycardia 30/min, blood pressure is 75 mmHg systolic, She is developing fluid overload and seems confused. Up to three boluses of atropine have been tried unsuccessfully.

Which of the following would be the correct way to manage this lady?

(Please select 1 option)

Atropine infusion

Transcutaneous pacing

Transvenous pacing wire Incorrect answer selected

Digibind antibodies This is the correct answer

Adrenaline infusion

Explanation

Hyperkalaemia is of major concern in digoxin toxicity. It increases the risk of AV block due to changes in the ionic gradient.

Indications for using Digibind include:

Progressive bradyarrythmias not responsive to atropine

Ventricular tachycardia/fibrillation

Potassium greater than 5 mmol/L

Acute ingestion >10 mg in adults

Serum concentration >15 ng/mL.

It is administered as an infusion over 30 minutes and average time to onset of action is 90 minutes. There should be evidence of recession of all signs and symptoms of toxicity including ECG changes.

In this lady her co-existing renal impairment is the most likely cause of toxicity and once treated for digoxin toxicity, it is important to consider carefully whether or not this drug be re-started in this patient.

Answer Statistics

1

1%

2

23%

3

30%

4

45%

5

4%

Times answered: 270